Nonlinear Magnetostatic Finite-Element Formulation for Models With Radial Symmetry

This paper discusses the implementation of nonlinear material properties in a 2-D magnetostatic finite-element solver for radially symmetric models. It is shown that, when saturation occurs, the particular dependence of the magnetic vector potential on the radial coordinate as required for radial symmetry is lost. Despite the 2-D geometrical symmetry, the weighted residual approach requires numerical quadrature points to be distributed along the direction of symmetry. The 2-D solver with radial symmetry is shown by calculating the performance of a dual-rotor permanent-magnet axial-flux machine.